Regardless of how much rain we often seem to get in the UK (and don’t we love to complain about it!), Dry Patch is a phenomena which happens to lawns when soil conditions have become so dry that water is no longer able to penetrate into the soil. This means that even when rain returns the soil has become hydrophobic (water-repellent). Dry Patch is also closely linked to another soil borne lawn problem called Fairy Rings.
This condition often happens in lawns that have become old or where the soil is poor and natural healthy bacteria cannot work efficiently. The affected areas of the lawn dry out as a consequence and turn brown as they are unable to absorb enough moisture to keep the grass plant healthy.
Hydrophobic conditions are caused by a white, waxy mycelium fungus in the soil which prevents any water from penetrating. Hence, the grass looks poor, especially during periods of dry weather when the underlying problem is exposed. It is often impossible for the soil to absorb any water, no matter how much you apply.
Dry Patch can be resolved with regular scarification, hollow-tine aeration and wetting agent applications. These treatments will improve the air and moisture flow into the root zone by removing thatch and breaking down surface compaction so it can absorb water and recover. Sometimes in bad cases of Dry Patch it is not possible to effectively treat or make improvements to the affected areas, so the best way forward is to dig out and remove the soil and replace it with new before re-seeding or turfing.